A typical illumination source for a display system makes use of one or more light sources that may include electric arc lamps, light emitting diodes, lasers, and other forms of solid-state lights, and so forth, to provide needed light. The light may be used to project an image created by a microdisplay, for example, onto a display plane. A digital micromirror device (DMD), one type of microdisplay, contains a large number of micromirrors that may individually pivot between an on state and an off state depending on an image being displayed, reflecting the light either onto or away from the display plane. The DMD, controlling the light reflected onto and away from the display plane, creates a projection of the image on the display plane.
The light from the light sources may be combined using beam shaping free space optics and dichroic technology. For example, optical lenses, filters, gratings, beam splitters, and so forth, may be used to focus, collimate, combine, split, filter, and otherwise process or manipulate the light from the light sources into a condition suitable for use in a display system.
The use of free space optics and dichroic technology has enabled fully operable illumination sources. However, with a continued push for smaller display systems, even pocket-sized display systems, the physical size of illumination sources using free space optics and dichroic technology may hamper the development of extremely small display systems.